#include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<iostream>
#include<queue>
#include<vector>
#include <bitset>
#include <cmath>
#include <limits>
#include <iostream>
using namespace std;
#define INF 100000
#define MAX 100000
#define MOD 1000000007n
typedef long long ll;
typedef pair<int,int> P;
typedef pair< pair<int,int>, int> p; 
#define bit(n,k) ((n>>k)&1) /*nのk bit目*/
#define rad_to_deg(rad) (((rad)/2/M_PI)*360)

int main(){
    ll N;
    cin>>N;
    if(N%4==3) cout<<"X"<<endl;
    else cout<<"O"<<endl;
}